Tight versus less tight 1-hour postprandial glycemic target in women with gestational diabetes mellitus - a single-center cohort study

Objectives: We aimed to assess the impact of the change of 1-hour postprandial glycemic target from < 6.7 mmol/L (120 mg/dL) to < 7.8 mmol/L (140 mg/dL) on gestational diabetes mellitus (GDM) treatment and pregnancy outcomes.

Material and methods: In a retrospective analysis of 1021 GDM patients from the Department of Metabolic Diseases, University Hospital in Cracow, Poland, we compared insulin therapy regimens and pregnancy outcomes between women admitted in 2014-2016 (before the change) and in 2018-2019 (after it).

Results: A total of 377 patients were admitted between 2014 and 2016 (TIGHT group) and 644 between 2018 and 2019 (LESS TIGHT group). Women from the LESS TIGHT group were older (32 vs 30 years, p < 0.001) and gained less weight during pregnancy (7.0 vs 9.0 kg, p < 0.001). There was no change in the frequency of any insulin therapy (51.6% vs 56.1%, p = 0.168). In the LESS TIGHT group, the basal insulin-only model was used more frequently (32.5% vs 10.2%, p < 0.001), while the prandial insulin and basal-bolus model less frequently (23.6% vs 42.6% and 21.4% vs 36.7%, p < 0.001, respectively) than in the TIGHT group. There were no differences in the frequency of cesarean sections, preterm births, Hbd of delivery, mean birth weight or prevalence of perinatal complications.

Conclusions: Less tight glycemic targets in women with GDM, compared to tighter targets, were associated with less frequent use of prandial insulin, with insulin therapy often limited to basal administration. The change in glycemic targets did not affect the prevalence of adverse pregnancy outcomes, providing evidence supporting new recommendations.